Control device for radio receiving sets



Dec. 27, 1938. SQLQMON 2,141,770

CONTI YOL DEVICE FOR RADIO RECEIVING SETS Filed Apz il e, 1937 ii. i yfi- 74 5 97 i 17 2 $10M y i Z6 =.1 10 x F1 29 I /I 24 m- YKR INVENTOR I Guillenrno Solomon ATTORNEYS Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE Guillermo Solomon, Santiago, Dominican Republic Application April 6, 1937, Serial No. 135,207

1 Claim.

This invention relates to control devices for radio receiving sets, an object of the invention being to provide an improved arrangement of resistor, rolling contact member, and disk fixedly 5 secured to a manually operated shaft so as to cause the rolling contact member to move along the resistor when the shaft is manually operated to control the loud speakers output.

The invention embodies many novel features of construction and combinations and arrangements of parts, all of which will be more fully hereinafter described and pointed out in the claim.

In the accompanying drawing Fig. l is a view in longitudinal section through my improved device;

Fig. 2 is a view in elevation, the view being taken on the line 22 of Fig. l;

Fig. 3 is a fragmentary view in section on the :0 line 3-3 of Fig. 2;

Fig. 4 is a fragmentary View in section on the line 4-4 of Fig. 2;

Fig. 5 is a view in elevation of my improved spring member;

Fig. 6 is a fragmentary view in elevation illustrating the groove in the shaft to receive the spring member;

Fig. 7 is a view similar to Fig. 6, illustrating a modified shape of groove;

Fig. 8 is a view in section through the resistor showing that the resistor may have a groove in its operating face; and

Fig. 9 is a view illustrating a modified form of resistor.

I ll represents a circular casing provided on one face with concentric outer and inner walls I l and I2, the outer wall being appreciably longer or deeper than the inner wall, and these walls are connected by radial webs l3, as clearly shown i0 in Fig. 2 of the drawing. 4 represents my improved resistor which is located against the inner face of the casing Ill and at its ends extends through slots |5 in the webs I3, and is provided at its ends with terminals or binding posts I6 and I! which are outside of the casing Ill. The casing l0 one one face is provided with a threaded nipple l8, which is adapted to receive nuts (not shown) for clamping the same to the chassis of a radio receiving set. The inner face of the casing 50 is formed with a bushing I9 and a shaft extends through the nipple I8 and bushing l9 and has secured thereon a metal disk 2| and a covering disk 22 of insulation which acts as a closure for the casing. These disks 2| and 22 are pref- 55 erably secured between annular shoulders 23 and 24 on the shaft, and it is understood that they are fixedly secured to the shaft so as to turn therewith. The resistor I4 intermediate its ends is provided with an extension 26 which extends through the wall H and is secured to a lug 21 on the wall by means of a rivet 28, so that this rivet and extension may constitute a terminal or binding post for use when the device is used as a potentiometer.

The casing I0 is formed with a radially extending grooved opening 29 and the shaft 20 is formed with an annular groove 30, and a forked spring member 3| is positioned in the opening 29 and has its bifurcated end 32 straddling the groove portion of the shaft, and it will be noted that this bifurcated portion of the spring 30 is somewhat bowed so as to exert inward pressure on the shaft 20.

Between the disk 2| and the resistor I4 I locate a rolling contact member 33, which preferably constitutes a ball although it may be made of other shape and, of course, the particular materials employed in forming the resistor I4, ball 33, and disk 2| may be varied to suit the trade.

Fig. 7 illustrates a V-shaped form of groove 34 in the shaft 20, which may be employed instead of the shape of groove shown in Fig. 6, and Fig. 8 illustrates the idea of providing a depression or groove 35 in the operating face of the resistor so as to center the ball between the sides of the resistor. Fig. 9 is merely illustrative of the idea that the resistor may constitute more than a complete circle, and it will be noted in this figure that the resistor 36 corresponding to resistor I4 is in the nature of a coil with the terminals or binding posts 3'! and 38 at the ends thereof.

The spring member 3| not only exerts a longitudinal pressure on the shaft 20 to hold the annular shoulder 23 in mechanical contact with the bushing I9, but it also maintains a good electrical contact with the shaft. The disk 2| is of spring metal and is flexible and resilient and is so positioned that its point of contact with the ball 33 is more or less distorted so that it exerts a good frictional and electrical contact with the ball.

The operation is as follows: When the shaft is turned it will of course turn the disk 2| and the disk frictionally engaging the ball 33 will maintain the ball in frictional engagement with the resistor l4, so that when the shaft 20 is manually turned theball will be caused to roll along the resistor towards one end or other of the resistor, thus maintaining a good electrical contact at all times and affording an efficient and simple means for controlling radio receiving sets.

While I have illustrated and described What I believe to be preferred embodiments of my invention, it is obvious that various slight changes may be made with regard to the form and arrangement of parts Without departing from my invention, and hence I do not limit myself to the precise details set forth but consider myself at liberty to make such changes and alterations as fairly fall Within the spirit and scope of the claim.

I claim:

A device of the character described, including a on the shaft to maintain the bar in electrical and 1( frictional contact with the shaft.

GUIILERMO SOLOMON. 

